In view of the interest in leukocytes for use in a variety of applications, some methods for harvesting the leukocytes involve passing blood or blood products through commercially available leukocyte depletion filter devices (via the device inlet and through the device outlet) to capture leukocytes by the filter medium in the device housing, and subsequently eluting the leukocytes from the device by passing an elution fluid in the opposite direction through the filter device (via the outlet and through the inlet).
However, there is a need for devices and methods for improving the efficiency of recovery. These and other advantages of the present invention will be apparent from the description as set forth below.